A number of scenarios may be enabled via a peer-based, distributed storage system. Examples of such scenarios include peer-based textual and rich media advertising storage/caching/replication, peer-based digital photo and video storage and sharing, and peer-based video email. These scenarios tend to be cost prohibitive as centralized services, however, because storage costs can become unbounded in a data center.
Many websites are moving to purely advertising-based models with highly targeted advertisements that appear based upon knowledge previously learned from the user. For example, it is well-known that a great deal of demographic data can be collected about people, and quite a bit of information can be inferred based solely upon data collected in the clickstream of a website. Highly targeted ads may be based upon search keywords, for example. Such a scenario typically requires lots of storage.
Storage of such advertisements in a centralized manner has been done before. A difficulty, however, exists in certain markets, such as emerging markets, because a different cost structure may be needed to be able to efficiently store, forward, and cache the advertisements to the local machine. In many cases, it is cost prohibitive to centralize these ads and pay storage costs in a datacenter because the ads are generally localized into the various world-wide markets. Paying bandwidth costs to ship ads around the world is usually not an efficient or inexpensive model.
Existing solutions for photo sharing fall into two major camps: centralized storage (e.g., photos.msn.com) or point-to-point (“P2P”) photo sharing (e.g., Google's current version of “Picasa”). Centralized storage has clear limitations: if it is provided for free, the total space available for photo storage may be severely limited. On the other hand, typical user fees tend to be far in excess of what it would cost a user to simply buy their own disk. If they buy their own disk, however, then they are responsible for backing up the photos and may be severely limited in the number of people who could view the photos because most broadband connections throttle the upload speeds.
P2P photo sharing solutions, such as Groove or Google's current version of Picasa, make entire copies of the photos across all of the machines participating in a peer group. Though this sidesteps the storage cost and bandwidth issues described above, it introduces different problems. For example, if not many people are participating in the group, then there is a fair chance (depending upon the uptime of the various peers) that a participant's photos may not be available if their local copies were lost. In addition, this brute force solution requires 100% of all peers to store 100% of all photos. This tends to result in a great deal of redundant storage used across the entire peer group, and does not scale well.
Video messages delivered via email suffer from many of the same problems described above in connection with photo sharing, but they are even more massive in size (making storage costly). Delivery also tends to be unreliable, unless serviced from a central datacenter. Though live P2P video teleconferencing does not have the storage problems (because the video is consumed at the same time it is sent), it has further limitations around quality (limited by bandwidth) as well as synchronicity of the speaking parties.
Thus, there is a need in the art for distributed storage models that provide cost-effective mechanisms to enable peer-based services such as rich media advertising, photo/video sharing/storage, and video email, for example.